Executive Summary extract :Around 70 per cent of all the litter in the oceans is made of plastic. Pollution of the environment with plastics is a global environmental problem; with plastic debris contaminating habitats from the poles to the equator and from the shoreline and sea surface to the deep sea. Plastic pollution results from a highly heterogeneous mixture of litter types differing in origin, size, shape and polymer type. Some of the most numerous items are discarded single-use packaging together with rope, netting and sewage-related debris.The majority of this litter originates from the land with rivers providing an important pathway to the sea. Plastic pollution can be harmful to wildlife, human well-being and to the economy in the UK, its Overseas Territories (OTs) and internationally.There is extensive evidence that entanglement in, or ingestion of, plastics can cause injury and death to a wide range of marine organisms, including commercially important fish and shellfish. Plastic pollution is also hazardous for mariners and reduces the amenity value of coastlines necessitating costly ongoing clean-up operations.Globally, production of plastics exceeds 300 million tonnes per annum and it is likely that a similar quantity of plastics will be produced in the next eight years as was produced in the whole of the 20th century. It is without question that plastics bring many societal benefits, however it is evident that most of these benefits could be realised without the need for the release of plastics, to the natural environment. Plastic pollution in the sea is a symptom of a more systemic issue originating on land and related to the design, the use and the disposal of plastic items, particularly single-use packaging. To reduce it, a key priority is to focus on interventions and stewardship to help reduce the quantity of plastic waste generated by society and the associated release of litter to the ocean.